With a large kiln at about 2000 degrees F and a slumping mold. If you use plexiglass, depending on which one (acrylic, polycarbonate, ect) you can heat it to about 400 degrees F and bend it. SOMETIMES you can use thin plastic and bend it to shape, holding it in with the framework, but it will always be under stress and break easily. You could look into glass suppliers to see if the curve matches any semi-standard form. If the design is your own, you may be out of luck : (